* Add Auth emulator support for IdentityToolkit requests.
* Formatting.
* Store the emulator URL in FIRAuthRequestConfiguration.
* Add support for emulating the web widget and SecureTokenService.
* Explicitly cast NSInteger to long to fix warning.
* Add unit tests.
* Fix copyright notice text.
* Remove useEmulator from the public API and disable app verification features when using the emulator.
* Fix test.
* Revert changes to FIRPhoneAuthProvider -- these are unnecessary for emulator support.
* Fix test.
* Fix test.
* Address review comments.